<p>European water policy requires to carry out nine tests for characterisation of groundwater bodies status, including the development of joint transboundary groundwater management principles. </p><p>Gauja/Koiva and Salaca/Salatsi Rivers have a joint, Estonian/Latvian transboundary water cycle, including the groundwater recharge and discharge cycling. Despite the fact that groundwater is the only drinking water source in Gauja/Koiva and Salaca/Salatsi River basins and ensures the existence of many groundwater dependent ecosystems, the overall awareness of integrated cross-border management practice is still poorly understood and poorly linked in implementation of concrete groundwater protection actions. </p><p>Taking into account the above-mentioned aspects, Latvian and Estonian groundwater and groundwater dependent ecosystems specialists from research, nature protection and groundwater resources management institutions have joined forces in the project funded by the Interreg Estonia-Latvia program: "Joint actions for more efficient management of common groundwater resources in Estonia and Latvia "(WaterAct).</p><p>The ongoing Est-Lat project “WaterAct” (2020–2022) of joint transboundary groundwater management project organised into the three activity blocks: (1) The capacity building of the joint groundwater transboundary management through exchange of knowledge and best management practices between project partners and key experts in other European Union countries; (2) Assessment of groundwater resources in transboundary River basins to improve groundwater management in accordance with valid international directives; (3) Dissemination and outreach activities to increase the overall awareness of ecosystems friendly groundwater management and protection of key actors working with groundwater assessments and locals. </p><p>Firstly, the joint cross-boundary principles of identification and status assessment of shared groundwater bodies will be developed. Adaptation of existing knowledge, cross-boundary harmonization and development of needed methodologies will be used. </p><p>Secondly, the joint cross-boundary assessment principles will be implemented into groundwater resources management. The status assessment of shared groundwater bodies will be carried out in close cooperation between project partners to create materials necessary for the development of last River Basin Management Plans (2022-2027), required by the Water Framework Directive and Groundwater Directive.</p><p>Thirdly, the dissemination of project results will be carried out (1) by compilation of Guidelines of Groundwater Dependent Ecosystems for different levels and fields of decision making and experts, (2) by compilation of Spring Water Monitoring Guide for Volunteers and starting volunteer monitoring. For volunteer monitoring, a special web-based map application will be developed (allikad.info). </p><p> </p><p>The project of “Joint actions for more efficient management of common groundwater resources” (WaterAct, Est-Lat155) funded by ERDF Interreg Estonia-Latvia cooperation programme.</p>